xref: /freebsd/lib/libc/gmon/gmon.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #if defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)gmon.c	8.1 (Berkeley) 6/4/93";
34 #endif
35 #include "namespace.h"
36 #include <sys/param.h>
37 #include <sys/time.h>
38 #include <sys/gmon.h>
39 #include <sys/mman.h>
40 #include <sys/sysctl.h>
41 
42 #include <err.h>
43 #include <fcntl.h>
44 #include <inttypes.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 #include "un-namespace.h"
50 
51 #include "libc_private.h"
52 
53 struct gmonparam _gmonparam = { GMON_PROF_OFF };
54 
55 static int	s_scale;
56 /* See profil(2) where this is described (incorrectly). */
57 #define	SCALE_SHIFT	16
58 
59 #define ERR(s) _write(2, s, sizeof(s))
60 
61 void	moncontrol(int);
62 static int hertz(void);
63 void	_mcleanup(void);
64 
65 void
66 monstartup(u_long lowpc, u_long highpc)
67 {
68 	int o;
69 	char *cp;
70 	struct gmonparam *p = &_gmonparam;
71 
72 	/*
73 	 * round lowpc and highpc to multiples of the density we're using
74 	 * so the rest of the scaling (here and in gprof) stays in ints.
75 	 */
76 	p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
77 	p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
78 	p->textsize = p->highpc - p->lowpc;
79 	p->kcountsize = p->textsize / HISTFRACTION;
80 	p->hashfraction = HASHFRACTION;
81 	p->fromssize = p->textsize / HASHFRACTION;
82 	p->tolimit = p->textsize * ARCDENSITY / 100;
83 	if (p->tolimit < MINARCS)
84 		p->tolimit = MINARCS;
85 	else if (p->tolimit > MAXARCS)
86 		p->tolimit = MAXARCS;
87 	p->tossize = p->tolimit * sizeof(struct tostruct);
88 
89 	cp = mmap(NULL, p->kcountsize + p->fromssize + p->tossize,
90 	    PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
91 	if (cp == MAP_FAILED) {
92 		ERR("monstartup: out of memory\n");
93 		return;
94 	}
95 #ifdef notdef
96 	bzero(cp, p->kcountsize + p->fromssize + p->tossize);
97 #endif
98 	p->tos = (struct tostruct *)cp;
99 	cp += p->tossize;
100 	p->kcount = (u_short *)cp;
101 	cp += p->kcountsize;
102 	p->froms = (u_short *)cp;
103 
104 	p->tos[0].link = 0;
105 
106 	o = p->highpc - p->lowpc;
107 	s_scale = (p->kcountsize < o) ?
108 	    ((uintmax_t)p->kcountsize << SCALE_SHIFT) / o : (1 << SCALE_SHIFT);
109 	moncontrol(1);
110 }
111 
112 void
113 _mcleanup(void)
114 {
115 	int fd;
116 	int fromindex;
117 	int endfrom;
118 	u_long frompc;
119 	int toindex;
120 	struct rawarc rawarc;
121 	struct gmonparam *p = &_gmonparam;
122 	struct gmonhdr gmonhdr, *hdr;
123 	struct clockinfo clockinfo;
124 	char outname[128];
125 	int mib[2];
126 	size_t size;
127 #ifdef DEBUG
128 	int log, len;
129 	char buf[200];
130 #endif
131 
132 	if (p->state == GMON_PROF_ERROR)
133 		ERR("_mcleanup: tos overflow\n");
134 
135 	size = sizeof(clockinfo);
136 	mib[0] = CTL_KERN;
137 	mib[1] = KERN_CLOCKRATE;
138 	if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
139 		/*
140 		 * Best guess
141 		 */
142 		clockinfo.profhz = hertz();
143 	} else if (clockinfo.profhz == 0) {
144 		if (clockinfo.hz != 0)
145 			clockinfo.profhz = clockinfo.hz;
146 		else
147 			clockinfo.profhz = hertz();
148 	}
149 
150 	moncontrol(0);
151 	if (getenv("PROFIL_USE_PID"))
152 		snprintf(outname, sizeof(outname), "%s.%d.gmon",
153 		    _getprogname(), getpid());
154 	else
155 		snprintf(outname, sizeof(outname), "%s.gmon", _getprogname());
156 
157 	fd = _open(outname, O_CREAT|O_TRUNC|O_WRONLY|O_CLOEXEC, 0666);
158 	if (fd < 0) {
159 		_warn("_mcleanup: %s", outname);
160 		return;
161 	}
162 #ifdef DEBUG
163 	log = _open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY|O_CLOEXEC, 0664);
164 	if (log < 0) {
165 		_warn("_mcleanup: gmon.log");
166 		return;
167 	}
168 	len = sprintf(buf, "[mcleanup1] kcount 0x%p ssiz %lu\n",
169 	    p->kcount, p->kcountsize);
170 	_write(log, buf, len);
171 #endif
172 	hdr = (struct gmonhdr *)&gmonhdr;
173 	bzero(hdr, sizeof(*hdr));
174 	hdr->lpc = p->lowpc;
175 	hdr->hpc = p->highpc;
176 	hdr->ncnt = p->kcountsize + sizeof(gmonhdr);
177 	hdr->version = GMONVERSION;
178 	hdr->profrate = clockinfo.profhz;
179 	_write(fd, (char *)hdr, sizeof *hdr);
180 	_write(fd, p->kcount, p->kcountsize);
181 	endfrom = p->fromssize / sizeof(*p->froms);
182 	for (fromindex = 0; fromindex < endfrom; fromindex++) {
183 		if (p->froms[fromindex] == 0)
184 			continue;
185 
186 		frompc = p->lowpc;
187 		frompc += fromindex * p->hashfraction * sizeof(*p->froms);
188 		for (toindex = p->froms[fromindex]; toindex != 0;
189 		     toindex = p->tos[toindex].link) {
190 #ifdef DEBUG
191 			len = sprintf(buf,
192 			"[mcleanup2] frompc 0x%lx selfpc 0x%lx count %lu\n" ,
193 				frompc, p->tos[toindex].selfpc,
194 				p->tos[toindex].count);
195 			_write(log, buf, len);
196 #endif
197 			rawarc.raw_frompc = frompc;
198 			rawarc.raw_selfpc = p->tos[toindex].selfpc;
199 			rawarc.raw_count = p->tos[toindex].count;
200 			_write(fd, &rawarc, sizeof rawarc);
201 		}
202 	}
203 	_close(fd);
204 }
205 
206 /*
207  * Control profiling
208  *	profiling is what mcount checks to see if
209  *	all the data structures are ready.
210  */
211 void
212 moncontrol(int mode)
213 {
214 	struct gmonparam *p = &_gmonparam;
215 
216 	if (mode) {
217 		/* start */
218 		profil((char *)p->kcount, p->kcountsize, p->lowpc, s_scale);
219 		p->state = GMON_PROF_ON;
220 	} else {
221 		/* stop */
222 		profil((char *)0, 0, 0, 0);
223 		p->state = GMON_PROF_OFF;
224 	}
225 }
226 
227 /*
228  * discover the tick frequency of the machine
229  * if something goes wrong, we return 0, an impossible hertz.
230  */
231 static int
232 hertz(void)
233 {
234 	struct itimerval tim;
235 
236 	tim.it_interval.tv_sec = 0;
237 	tim.it_interval.tv_usec = 1;
238 	tim.it_value.tv_sec = 0;
239 	tim.it_value.tv_usec = 0;
240 	setitimer(ITIMER_REAL, &tim, 0);
241 	setitimer(ITIMER_REAL, 0, &tim);
242 	if (tim.it_interval.tv_usec < 2)
243 		return(0);
244 	return (1000000 / tim.it_interval.tv_usec);
245 }
246